One-dimensional ring structures form M13 viruses were constructed by two
genetic modifications encoding binding peptides and synthesis of a
heterobifunctional linker molecule. The bifunctional viruses displayed an
anti-streptavidin peptide and hexahistidine (SEQ ID NO: 4) peptide at
opposite ends of the virus as pIII and pIX fusions. Stoichiometic
addition of the streptavidin-NiNTA linker molecule led to the reversible
formation of virus-based nanorings with circumferences corresponding to
lengths of the packagable DNAs. These virus-based ring structures can be
further engineered to nucleate inorganic materials and form metallic,
magnetic, or semiconductor nanorings using trifunctionalized viruses.